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What Li-Polys do I need? - 1/2/2004 4:40 AM   
Flounder44


 

Posts: 4
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Last Login: 1/4/2004
From: , PA, USA
Status: offline 		I read in Park Flyer magazine that a Li-Poly pack is fully charged when each cell has reached 4.2 volts and it is fully discharged when each cell reaches 3 volts. I would assume that the Li-Poly chargers will not exceed the high limit, but how does one guarantee not going under the low limit? Does a speed control monitor this?

Also - I have 2 planes and would like to convert them to Li-poly - what battery pack would be best for both?:

#1 - Graupner Albatros - it now has a 280 motor with a 5A GWS GS100 speed control and a 6 cell 1000 MaH battery

#2 - Wattage Fokker Eindecker - it now has a 380 motor with a IC-30A speed control and 7 cell 1100 MaH battery.

I would like to buy two of the same batteries if that's possible - but don't know if the 5A speed control could handle the power that I need for plane #2.

Thank you for any information you can provide!

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RE: What Li-Polys do I need? - 1/2/2004 5:50 PM   
Greg Covey



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Last Login: 5/21/2012
From: Rochester, NY, USA
Status: offline 		Hi,

Although there are now Lithium "friendly" ESCs available, I have not had a problem in over 30 setups using LiPoly cells with regular ESCs. The 30 setups span from 1oz micro-flyers to 10lb, 7-foot planes.

To replace your 6-cell, 1000mAh pack on your Speed 280 setup, you want a 2-cell Lithium pack capable of delivering 6amps continuous.

Hobby Lobby sells some nice Lithium packs here.

The 2-cell 1200mAh (FM122) pack would work nicely. Other packs would also work that will vary the flying weight or duration to suit your specific needs. The lighter Kokam 340SHC cells can also provide 6amps continuous current and the heavier 1500HC cells will provide longer flight times than the 1200 cells but add an ounce to your flying weight.

For your Speed 400 (aka Speed 380) Eindecker setup, I would recomend a 2-cell Kokam 1500 pack.

The setup will limit your current draw so don't worry about the ESC rating alone. The 2-cell 1500 pack will work in both planes but the 1200 cells will be lighter for the Albatros.

Good luck!

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Visit my Web Hangar at www.gregcovey.com/rc.htm

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RE: What Li-Polys do I need? - 1/2/2004 11:09 PM   
Flounder44


 

Posts: 4
Score: 100
Joined: 1/1/2004
Last Login: 1/4/2004
From: , PA, USA
Status: offline 		Thank you for clearing that up for me. I was rather intimidated by all the data on the "new" li-polys.

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